Obese (120-150% of ideal body weight) hypertensive adults-will be placed on a weight reduction diet in the outpatient clinic and followed weekly. Blood samples and 24 hour collections of urine, for evaluation of a number of systems that may be involved in the decrease in blood pressure associated with weight loss, will be obtained at the following times: (a) before the diet begins: (b) when blood pressure has decreased by 5-10 mmHg in association with mild weight loss and (c) when the patient is close to ideal body weight. After the last collection, the patient will remain on the same diet for another week and will rake sodium chloride and calcium carbonate tablets in amounts needed to equal the original intake of sodium and calcium. Blood pressure will be monitored to see if there is any reversal of the blood pressure reduction.